The long term goal of this application is to understand the biological function of type XVI collagen. Collagens, which are major structural macromolecules of connective tissue, consist of at least 19 distinct types. Type XVI collagen is a recently discovered member of the collagen family. It possesses several structural features characteristic of the fibril associated collagen subgroup, whose members include type IS, XII, XIV, and XIX collagens. However, it is unique among collagens in that its long collagenous region is interrupted by multiple noncollagenous domains enriched in cysteines. Type XVI collagen mRNA is expressed at low levels in most tissues but at much higher levels in overy, testis and prosate tissue, suggesting that type XVI collagen plays critical roles in male and female reproductive organs. In this renewal application, experiemtns are proposed to continue investigating the function of type XVI collagen. The expression of type XVI collagenmRNa and protein in male and female reproductive organs will be examined in detail. Transgenic mice with the type XVI collagen gene inactivated or mutated will be prepared to study the in vivo function of type XVI collagen. Recombinant type XVI collagen chains will be prepared to study their binding interactions with other extracellular matrix proteins. The transcription regulation type XVI collagen gene will be studied by characterization of the promoter region of the gene.